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A production process of annealing and pickling for 409l cold-rolled steel strip

A production process and technology for cold-rolled strip steel, applied in the field of annealing and pickling production process of 409L cold-rolled strip steel, can solve problems such as increasing production cost, and achieve the effects of saving investment, reducing production cost, and reducing the generation of oxide scale

Active Publication Date: 2016-03-02
WISDRI ENG & RES INC LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] In view of the above problems, the object of the present invention is to provide a 409L cold-rolled steel strip annealing and pickling production process, aiming to solve the technical problem that the existing method requires additional nitric acid electrolytic pickling equipment and increases production costs

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  • A production process of annealing and pickling for 409l cold-rolled steel strip

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Embodiment 1

[0030] The annealing and pickling production process of 409L cold rolled strip steel provided in this embodiment is as follows:

[0031] A1. Send the strip steel to the annealing furnace for annealing treatment. The temperature control of the annealing furnace includes two periods. In the first period, the temperature of the strip at the exit of the annealing furnace is 660°C and the excess oxygen concentration is 7.5%; in the second period, The strip temperature at the exit of the annealing furnace is 950℃, the excess oxygen concentration is 7.5%, and the strip annealing time is 21s;

[0032] A2. Send the annealed strip steel to the electrolytic pickling section, where the concentration of the neutral salt solution is 180g / L, the concentration of nitric acid is 130g / L, the pH value of the electrolytic acid solution is adjusted by adding sulfuric acid, and the pH value is controlled at 3.8. Metal ion concentration is 6g / L, temperature is 63℃, current density is 10A / dm 3 , The elect...

Embodiment 2

[0035] The annealing and pickling production process of 409L cold rolled strip steel provided in this embodiment is as follows:

[0036] B1. Send the strip steel to the annealing furnace for annealing treatment. The temperature control of the annealing furnace includes two periods. In the first period, the temperature of the strip at the exit of the annealing furnace is 680℃ and the excess oxygen concentration is 8.5%; in the second period, The temperature of the strip at the exit of the annealing furnace is 970℃, the excess oxygen concentration is 8.5%, and the strip annealing time is 46.5s;

[0037] B2. Send the annealed strip steel to the electrolytic pickling section, where the concentration of neutral salt solution is 200g / L, the concentration of nitric acid is 140g / L, the pH value of the electrolytic acid solution is adjusted by adding sulfuric acid, and the pH value is controlled at 4.2. The metal ion concentration is 10g / L, the temperature is 67℃, and the current density is...

Embodiment 3

[0040] The annealing and pickling production process of 409L cold rolled strip steel provided in this embodiment is as follows:

[0041] C1. Send the strip steel to the annealing furnace for annealing treatment. The temperature control of the annealing furnace includes two periods. In the first period, the temperature of the strip at the exit of the annealing furnace is 670℃ and the excess oxygen concentration is 8%; in the second period, The strip temperature at the exit of the annealing furnace is 957°C, the excess oxygen concentration is 8%, and the strip annealing time is 39s;

[0042] C2. Send the annealed strip steel to the electrolytic pickling section, where the concentration of the neutral salt solution is 190g / L, the concentration of nitric acid is 135g / L, the pH value of the electrolytic acid solution is adjusted by adding sulfuric acid, and the pH value is controlled at 4.0. Metal ion concentration is 8g / L, temperature is 65℃, current density is 12A / dm 3 , The processin...

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Abstract

The invention is suitable for the technical field of stainless steel production technologies, and provides a 409L cold-rolled strip steel annealing-pickling production process. The production process comprises an annealing treatment step, an acid electrolysis step and a pickling step, and corresponding process parameters are required to be set in each step. According to the 409L cold-rolled strip steel annealing-pickling production process, the electrolytic pickling efficiency can be improved by controlling the excess oxygen concentration of each section of an annealing furnace, adding sulfuric acid and nitric acid solutions in a neutral saline solution, and controlling the PH value of the solutions to be 3.5-4.5; chromium oxides, iron oxides and chromium-depleted layers on the surface of a strip steel can be completely removed after electrolytic pickling; meanwhile, an annealing-pickling line which only can be used for producing FeCrNi series cold-rolled stainless steel in the past also can be used for producing cold-rolled 409L ultra-pure ferrite stainless steel.

Description

Technical field [0001] The invention belongs to the technical field of stainless steel production, and in particular relates to a 409L cold rolled strip steel annealing and pickling production process. Background technique [0002] At present, when cold-rolled 409L ultra-pure ferritic stainless steel strip is annealed, the excess oxygen concentration in each heating section in the furnace is basically the same, generally between 3% and 8%. However, the amount of oxide scale on the surface of the strip after annealing More, so that the subsequent pickling time is longer, and it will also reduce the surface quality of the strip after pickling. [0003] After annealing, 409L cold-rolled stainless steel generally adopts neutral salt electrolytic pickling and nitric acid electrolytic pickling process; because the surface of 409L cold-rolled stainless steel strip is generally dominated by iron oxide, the content of chromium oxide is less, and the neutral salt Electrolytic pickling has a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C23G1/08C21D9/56C25F1/06
Inventor 李勇华胡斯尧陈连龙
Owner WISDRI ENG & RES INC LTD